An air-conditioning apparatus installed on a roof part of a railroad vehicle, which is operated in a subway, for example, is often used exclusively for cooling. In winter when heating is required, a railroad vehicle including such an air-conditioning apparatus supplies warm air into a cabin, by operating an electric heater provided below seats inside the cabin.
Generally, an indoor chamber and an outdoor chamber are formed inside a main body of a vehicle air-conditioning apparatus. An indoor air-sending device and an indoor heat exchanger are provided in the indoor chamber. A compressor, an outdoor air-sending device, and an outdoor heat exchanger are provided in the outdoor chamber.
There has been a conventional vehicle air-conditioning apparatus that has an outdoor air inlet formed in an upper part of a main body of the vehicle air-conditioning apparatus, and heats the inside of a cabin by introducing outdoor air into the main body through the outdoor air inlet during its heating operation, and exchanging heat between the outdoor air introduced into the main body and refrigerant flowing through a refrigerant pipe of an outdoor heat exchanger.
Also, there has been a conventional heat pump (cooling and heating) air-conditioning apparatus (Patent Literature 1) that includes an outdoor air-sending device provided at the center of an outdoor chamber, and outdoor heat exchangers provided on both side surfaces of the outdoor air-sending device, and discharges outdoor air, which is introduced into the main body from an outdoor air inlet formed in a side surface of the main body, through an outdoor air outlet formed in an upper surface of a main body.
Also, there has been a conventional air-conditioning apparatus (Patent Literature 2) that rotates an eccentric multi-blade outdoor air-sending device provided on an inner side surface of an outdoor chamber, to discharge outdoor air, which is sucked from an outdoor air inlet formed in the side surface of the outdoor chamber, through an outdoor air outlet formed in the side surface of the outdoor chamber. In the air-conditioning apparatus of Patent Literature 2, a partition plate is provided on the outdoor air outlet side inside the main body, so that it is spaced apart from a peripheral surface of the casing where the strongest centrifugal force is generated, within an area where a sufficient centrifugal force is generated, and thus an airflow containing relatively heavy substances such as snowflakes can be guided to the peripheral surface of the casing, and be discharged to the outside from the outlet.